How do you cure the low throttle "jump"?

5 replies to this topic
  • lomitamike

Posted April 04, 2002 - 09:45 AM


Thanks for suggestions in advance.

I have a US 2001 WR 426 that jumps just off-idle. I like to ride slow technical stuff and the unpredictability of the throttle is killing me. This is the order of mods done to my bike. Removed airbox lid, replaced baffle with a Vortip, cut down throttle stop, bent down grey wire tab in connecter. Usually ride between sea leval & 7000 ft. I've searched through the jetting and BK mod threads and from what I've read it looks like the BK mod will help this part of the throttle along with,
OBELN needle #5 clip
#168 main
#48 PJ
#100 PAJ
Does anyone have any other/better suggestions? Im a little timid about digging into my carb.
Thanks again. Mike

  • Taffy

Posted April 04, 2002 - 10:05 PM


don't go to 48PJ/100PAJ. that's gauranteed to give you a "bog" off of idle. this BTW is what you're describing i think.

stick with the 42PJ and get a 75PAJ. then start playing with the PS underneath the carb by doing little snap wheelies and adjust it in and out. i think that 1 to 1.5 turns out should do it.

the rest looks good. as for the BK mod on the '02's? it must squirt for less than .5 seconds and i think they come already set like that from the factory.


  • Ron_in_SoCal

Posted April 04, 2002 - 11:03 AM


I would suggest a 10oz or 12oz flywheel weight. This will reduce the violent power delivery and store energy for low-end "chugging" in technical conditions. The BK mod makes the throttle response much more crisp off idle (00 and 01 model years), thus it would only increase the snap you are trying to avoid, but it does not apply to your 02.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • lomitamike

Posted April 04, 2002 - 12:55 PM


Thanks Ron and Taffy, I don't know how much difference there is between 01 and 02 but I have 01.

  • Ron_in_SoCal

Posted April 04, 2002 - 01:03 PM


Doh! I guess I should pay more attention.

  • Bill

Posted April 04, 2002 - 04:29 PM


You might want to consider YZ timing the bike. I think it softened the bottom a little and moved the power up the RPM range. FOR ME, it makes the bike easier to ride in the tight stuff.



Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.